P0492: Secondary Air Injection System Insufficient Flow (Bank 2)

What does P0492 mean?

The bank 2 secondary-air monitor detects less airflow than expected. Bank 2 is opposite cylinder 1, and a local blocked passage or valve fault can cause this result even with a functioning shared air pump.

Generic OBD-II definition: Secondary Air Injection System Insufficient Flow (Bank 2). Confirm applicability in your vehicle service information.

Common causes

• Blocked bank 2 secondary-air passages
• Stuck check/combi valve
• Leaking vacuum control or air hose
• Weak pump or electrical supply fault

Symptoms

• Check engine light
• Usually normal warm-engine operation
• Possible noisy secondary-air operation

Diagnostic focus

Confirm which exhaust bank is bank 2 before dismantling anything. Similar-looking hoses and valves can make it easy to repair the wrong bank.

Can I keep driving with P0492?

Severity: Low If the light is steady and the engine runs normally, schedule diagnosis. Stop for smoke, a burning electrical smell, or severe rough running; those are not normal secondary-air symptoms.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Compare bank 2 and bank 1 cold-start response
• Inspect bank 2 hoses and control valve
• Verify air delivery before authorizing cylinder-head passage cleaning

Sources & review

• OBD-Codes.com: P0492
• TroubleCodes.net: generic code definitions

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.